This invention relates to an apparatus for manufacturing dual component fibers from thermoplastic materials, and more particularly to a spinner apparatus for centrifuging dual component fibers from two streams of molten thermoplastic materials such as glass or other mineral fibers or polymer fibers.
Fibers of glass and other thermoplastic materials are useful in a variety of applications including acoustical or thermal insulation materials. Common prior art methods for producing glass fiber insulation products involve producing glass fibers from a rotary process. A single molten glass composition is forced through the orifices in the outer wall of a centrifuge commonly known as a spinner, producing primarily short, straight glass fibers.
The temperatures of molten glasses used in rotary fiberizing processes may exceed 2000.degree. F. (1093.degree. C.). Because of the high temperatures involved and the high rotational speeds of the spinners, the materials of construction for such devices present many demands on those materials to withstand those conditions. Corrosion resistance is also required so that the orifices in the spinner maintain their designed size and shape.
A modification of conventional glass fibers, which are usually straight fibers, is the use of fibers which are curly (helical) in shape. These fibers can be made by joining two distinct glass streams, commonly referred to as the A glass and B glass streams, and centrifuging the dual glass stream into a curly (helical) fiber.
Stalego, U.S. Pat. No. 2,998,620, discloses curly (helical) glass fibers of bicomponent glass compositions. Stalego discloses producing staple curly fibers by passing two glass compositions having differing coefficients of thermal expansion through the orifices of a spinner. The glasses are extruded as a dual glass stream in aligned integral relationship such that the fibers curl naturally upon cooling due to the differences in their coefficients of thermal expansion. Stalego discloses in one embodiment a spinner having vertically aligned compartments separated by vertical baffles around the periphery of the spinner, with alternate compartments containing the different glasses. The patentee teaches that an orifice wider than the baffle is to be drilled where the baffle intersects the spinner peripheral wall. As the orifice is wider than the baffle, the orifice is in communication with both of the vertical compartments on either side of the baffle, and both the A glass and B glass will exit the spinner from the orifice, forming a dual glass stream.
However, there remains a need in this art for improving the delivery of dual streams of molten glasses to form dual glass or other thermoplastic fibers.